Folding steel square.



I. BARKER. FOLDING STEEL SQUARE. APPLIGATION FILED DB0. 13, 1910. Bmw-WED 1511.?11, 1912. 1,043,502.

Patented Nov. 5, 1912.

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JOHN BAKKER, F CHICAGO, ILLINOIS.

FORUM@ STEEL SQUARE.

pecication of Letters Patent.

tiled Zecember w, figlia-Serial No. 597,058. Renewed April 11i, 1912.;y Serial No. 690,041.

dit all renom et may conceive:

ide it known that l, Joran Banner, a citiren ont the United States, residing at Chiin the county of @ook and State of .ln lois, have invented certain new and useiul improvements in Folding Steel Squares,

of which `the following is a speciication.

My present invention relates to carpenters steel squares of that type in which the arm lo and blade are arranged to fold together, and more particularly to improvements upon the steel squares described and claimed in my Patents Numbers 952,176' and 952,177, both issued to ine March. 15, 1910.

llhe principal object of my present. invention is the provision or a folding steel square,

embodying a protractor, andrepresentative .figures olf' the polygons so often used in the trede, and so important thereto, these figures having angle designations in relation to the protractor that is each figure is provided 'v 'th the graduation of the protractor scale ich. the blade must be set to obtain its l urther objects, and advantages arising nu novel details of structure, will be here- `ter made apparent, from the accompanyi descri tion, in which reference is made to the drawing forming a part of this speciq' i n, nd in whichure 1' is a plan view ot' my improved square, showing the same in the open position. Fig. 2 is a similar view of a portion thereof in the foldedposition. Fig. 3 L5 is an end view of Fig. 2. Fig. is a detail section taken on line Lis- 4l oli Fig. 1. Fig. 5 is a similar view on the line 5 5 of Fig. l, and Fig. 6 is a transverse section through the arm, taken on the line 6-6 of Fig. 1.

Referring now to these ligures, the arm A, and the blade B oi my improved .steel square, are both provided....along-their inner and outer edges with the usual raduations, and the arm A is further provlded with a cen- 415 'trai and longitudinally extending series of polygonal figures, each of which is desig-4 nated with its respective name, the number of its sides, and the angle required to cut the same. f 5o Adjacent to one end, and at its inner edge,

the arm A is provided with a substantially der to tlorm a convex shoulder Z1. The, arm,

A 'is also provided, around thecut-out pon.l tion '0; and shoulder b',fwith an under-'eilt recess in which projects-the extension rib c of the reduced semi-circular tongue d ofthe blade B, which tongueinteriits the arm recess or cut-out portion Inland is provided Patented Nov. 5, 1912.

with a transverse opening 'adapted to aline with a similar opening through the arm a,

when the arm and blade are placed together in proper relation. The pivotal connection between the arm and lblade is formed by telescoping sleeves 10 and 11, the former of which extends downwardly within theaforementioned openings, through the tongue d, and the latterof which' extends upwardly and within sleeve 10, through the reduced part of arm A. The heads of these sleeves 10 s and 11 are counter-sunk so that their surfaces lie flush with the surfaces of the vtongue al and arm a, and the inner sleeve 11 shoulderof the arm A, when the arm and blade are exactly at right angles.

The arm A is provided with a recess f extending parallel with the inner edge therel' of and inwardly from the recess o, in which recess f is disposed a sliding locking meinber g', this member having a beveled outer end, and tensioned to project its said beveled end toward and within the recess o, by means of the free engaging end of a spring 13, the opposite end of which is locked within a channel in the arm A, by means ofa transverse pin 14. The semi-circular edge of the tongue 0l is provided with a cut-out portion 7i, so positioned as to receive the beveled end of the locking slide g `when the arm A and blade B arel exactly at right angles, thus locking the sam-e from inward folding movement. The arm A is further provided with. a recess in its surface, extending at an angle from its recess a, and with a transverse threaded opening communieating with said angular recess. Fitted within this angular recess is an apertured plug j, at one end of which is a reduced extension la, which overlies the lrib of the blade tongue d and the end of which is flush vthe blade B in selected angular adjustment in relation to the protractor scale' m, formed around the edge of the arm recess a, and with which a pointer n, of the tongue ci cooperates.

From this it will be seen that my improved square may be readily and easily folded by sliding the locking plate g inwardly, and swinging the blade B against the arm A to the position shovvn in Fig. 2.

It Will be further seen that the arm and blade may be. rigidly-locked in the open position by means of the locking plate g and that said blade B may be quickly and `rigidly locked in selected angular adjustment with relation to the arm A, by means of the plug j and that the protractor scale when utilized in accordance With the designations of the polygons, Will enable a mechanic to lay out numberless angles impossible with .the ordinary square.

I claim 1. In a folding steel square, the combination of an arm having a semi-circular recess at one end, and provided With 4an undercut channel surrounding said recess, a blade having a reduced semi-circular tongue interfitting, and pivoted Within, said arm recess, and provided with a rib extending around its edge and fitting Within said under-cut channel, said arm having a second recess extending at an angle from its first named-recess, a bearing plug mounted in said last named recess and having a reduced extension overlying the said rib of said tongue, and an adjustable member for securing said bearing plug in position and compressing the same upon said rib to lock said blade in selected angular adjustment with relation to the said arm.

2. In a folding steel square, the combination of an arm having a semiecircular recess at one end and provided With an undercut channel surrounding said recess, a blade having a reduced semi-circular tongue interfitting, and pivoted Within, said arm recess, and provided With a rib extending around its edge and fitting Within said under-cut channel, means carried by the arm to lock the blade at right angles thereto, said means being engageable Within a recess of the blade tongue, and other means carried by the-arm to lock the blade at a selected degree of angle With relation thereto, said last named means comprising a plug bearing upon. and frictionally engageable with, the tongue rib.

In testimony whereof I aiix my signature 'in presence of two Witnesses.

JOHN BAKKER.

Witnesses:

MYRON G.' CLEAR, ANNA M. MENGEL. 

